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New Member

Help with BGP convergance.....

We have a WAN on MPLS that is using

BGP. We are getting 25 to 35 second convergance but we need to do better. I have the router config's and a drawing of the

network if someone thinks they could help us improve this. Thanks in advance.......

  • WAN Routing and Switching
18 REPLIES

Re: Help with BGP convergance.....

Is it eBGP or iBGP that you're using? You can change timers per neighbor to help with convergence. Something like:

neighbor x.x.x.x timers 5 15

BGP will select the lower timer of the 2 peers (meaning if your peer is 60 180 (default), it will scale down to match yours.)

There is a recommendation for not going lower than 20 seconds because it can increase the chance of bgp flapping.

HTH,

John

HTH, John *** Please rate all useful posts ***
New Member

Re: Help with BGP convergance.....

We have adjusted the timers but we still see the 25 to

35 seconds to converge.....I wonder if we are missing something in the config????

Re: Help with BGP convergance.....

Can you post the config?

HTH, John *** Please rate all useful posts ***
New Member

Re: Help with BGP convergance.....

Here's the configs from the routers ..... I'll post a drawing next

Thanks again for your help

James

New Member

Re: Help with BGP convergance.....

Here's the drawing

Let me know if you have any questions about this.....

Re: Help with BGP convergance.....

Gonna take me a little time to look at this. Where are these routers in your diagram? I don't see the AS listed that you have in the configs.

John

HTH, John *** Please rate all useful posts ***

Re: Help with BGP convergance.....

There are a couple of things that you can try that I don't see in your config. There's an option in BGP called fall-over. It helps speed up convergence on the

detection of a loss of the peer. I would apply it to the iBGP peers and see if that helps with your convergence. You can also try to enable graceful-restart to see if that helps as well.

HTH,

John

HTH, John *** Please rate all useful posts ***
New Member

Re: Help with BGP convergance.....

We looked at fall over but it said it needed host routes and not loopbacks....it didn't seem to fit with our design....please take all the time you need.....I get off work between 5 and 5:30 EST....I'll most likely be back on tonight from home.....this amusment never ends.....

New Member

Re: Help with BGP convergance.....

John,

     I went back in and looked at the timers again.....I reset them and it inproved the convergance greatly....we now see 6-7 seconds until the network convereges....I'm not sure we could do better than that....so today more testing ....thanks for your help...

James

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